Tracking Policy Failure Statistics

Users can track the number of calls that Cisco Unified Border Element (SP Edition) rejected based on the rules established in the number analysis policies, routing policies, or Call Admission Control (CAC) policies. Users can also view and query the policy failure statistics associated with these rejected calls, which can help them determine whether changes need to be made to the existing policies.

Cisco Unified Border Element (SP Edition) was formerly known as Integrated Session Border Controller and may be commonly referred to in this document as the session border controller (SBC).

For a complete description of the commands used in this chapter, refer to the Cisco Unified Border Element (SP Edition) Command Reference: Unified Model at:

Policy Failure Statistics for a Specified Time Interval

Table 42-1 lists the command to view and clear the failure statistics on the specified signaling border element (SBE) for a certain time interval.

Table 42-1 Commands for Time-Based Policy Failure Statistics

clear sbc service-name sbe policy-failure-stats

Clears the policy failure statistics for the current and previous time interval.

Policy Set and Per-Entry Statistics

To determine whether calls failed due to policies configured in the routing, number validation, or CAC tables, users can view the policy failure statistics for a specific policy table or table entry. Table 42-2 lists the commands to view and clear the statistics on policy tables associated with a policy set.

Table 42-2 Commands for Statistics for PolicyTables in a Policy Set

show sbc service-name sbe cac-policy-set policy set-id tables

Displays a summary of the CAC policy tables associated with the given policy set, including the number of failed calls.

clear sbc service-name sbe cac-rejection-stats

Clears all CAC policy failure statistics.

show sbc service-name sbe call-policy-set policy set-id tables

Displays a summary of routing policy tables associated with the given policy set, including the number of failed calls.

The statistics are collected at 5 minute intervals past the hour (that is, at 0, 5, 10, 15 minutes, and so on past the hour). For example, the periods covered by the various buckets at 12:43 would be as follows:

current five minutes: 12:40-12:43

previous five minutes: 12:35-12:40

current 15 minutes: 12:30-12:43

previous 15 minutes: 12:15-12:30

current hour: 12:00-12:43

last hour: 11:00-12:00

current day: 00:00-12:43

last day: 00:00-24h - 00:00

A counter can keep increasing. It keeps a count of events that have completed. When reporting the value of a counter, it's the sum total of events that happened in the period. Some examples of counters are total call attempts, failed call attempts, and active call failures.

A gauge is a counter that can go up and down. It typically tells you how many of something there are now. When reporting the value of a gauge, it's either the current value, or when measured over a longer time period, it's the average value during the period. Some examples of gauges are active calls, activating calls, and deactivating calls.

Policy Failure Statistics and Hunting

If the CAC module refuses a call or if a call cannot be signaled to the chosen destination adjacency because of a negative or no response, call hunting occurs. Call hunting is the process of selecting an alternative adjacency from the routing tables and retrying the call using the newly selected destination adjacency.

Hunting continues until one of the following conditions is fulfilled:

The call gets connected.

No further adjacencies are available for retry.

The call has been hunted too many times.

Global Statistics and Call Hunting

If a call gets connected after hunting, Cisco Unified Border Element (SP Edition) does not include it in any of the following global statistics:

Total call setup failures

Total call setups failed due to number analysis

Total call setups failed due to routing

Total call setups failed due to CAC

CAC failure due to number of calls limit

CAC failure due to call rate limit

CAC failure due to media channels limit

CAC failure due to bandwidth limit

If a call fails after number analysis, hunting does not occur. Cisco Unified Border Element (SP Edition) includes it in the following global statistics:

Total call setup failures

Total call setups failed due to number analysis

If a call fails the first time it is routed because no destination adjacency is found in the routing table, then Cisco Unified Border Element (SP Edition) includes it in the following global statistics:

Total call setup failures

Total call setups failed due to routing

If a call fails because a CAC policy refused it permission to proceed, Cisco Unified Border Element (SP Edition) includes the failure in the total call setups failed due to CAC statistics. Additionally, the call is included in one of the following statistics depending on the nature of the CAC limit:

CAC failure due to number of calls limit

CAC failure due to call rate limit

CAC failure due to media channels limit

CAC failure due to bandwidth limit

Per-table and Per-entry Statistics and Call Hunting

If a call undergoes N iterations of hunting, then it traverses the number analysis tables once, and the routing and the CAC tables N times. But the CAC tables can reject the call each time it traverses the CAC table. For each time the CAC table rejects the call, Cisco Unified Border Element (SP Edition) finds the table and entry that was responsible for setting the CAC limit, and increments the following:

Number of calls refused by the CAC table

Number of calls refused by the table entry

Per-adjacency and Per-Account Statistics and Call Hunting

If a call gets connected after hunting, Cisco Unified Border Element (SP Edition) does not include it in the following per-account or per-adjacency statistics:

total call setup failures

total call setups failed due to number analysis

total call setups failed due to CAC

CAC failures due to rate limit

CAC failures due to media channels limit

CAC failures due to bandwidth limit

If a call fails due to number analysis, then hunting does not occur and Cisco Unified Border Element (SP Edition) includes the call in the following per-account and per-source adjacency statistics:

total call setup failures

total call setups failed due to number analysis

If a call fails in the routing tables before hunting occurs, Cisco Unified Border Element (SP Edition) includes the call in the following per-source account and per-source-adjacency statistics:

total call setup failures

total call setups failed due to routing

A call included in the total call setup failures statistics is included in the per-source adjacency, per-destination-adjacency, per-source-account adjacency, and per-destination account statistics. Additionally, if the most recent hunting attempt failed because a CAC policy refused the call permission to proceed, Cisco Unified Border Element (SP Edition) includes the failure in the total call setups failed due to CAC statistics in the per-source-adjacency, per-destination-adjacency, per-source-account, and per-destination-account statistics. The call is also included in one of the following statistics depending on the nature of the CAC limit depending on the nature of the CAC limit: